UPC-MAC: A Power Control MAC Protocol for Underwater Sensor Networks

After comparing the spatial reuse efficiency between RF based networks and acoustic based networks in terms of our newly defined metric, spatial reuse index, we found that the spatial reuse efficiency in acoustic based networks is significantly lower due to the relatively low spreading loss of acoustic signals, which further degrades the network throughput. To improve the system performance, we propose a slotted based Underwater Power Control MAC protocol (UPC-MAC), which leverages transmission power and long propagation delays to enhance the spatial reuse efficiency. UPC-MAC is a reservation based channel access scheme and makes use of long propagation delays to collect neighboring nodes’ sending requests and channel information between these senders and receivers. With such information, UPC-MAC allows for concurrent transmissions by applying Nash Equilibrium to transmission power adjustment , which can be done on every sending node in a distributed way. Simulation results show that UPC-MAC outperforms Slotted FAMA in terms of network goodput by 15-20% and 35-60% respectively in two representative network scenarios.